The present invention relates generally to a magnetic disk medium and a magnetic recording system, and more specifically to a magnetic disk medium and a magnetic recording system, which have main applications in computer peripheral recording equipment.
With increases in the recording capacity of computers, the recording capacity of magnetic recording systems tend to become increasingly larger. For the purpose of linear recording density increases, an important consideration is how an array of recording domains in a magnetic recording layer of a magnetic disk medium, formed by a write magnetic field generated from a magnetic head, are made minuscule.
To make the recording domains minuscule, it is particularly important to narrow the spacing between the foremost end of the magnetic head nearest to the magnetic recording layer and the magnetic recording layer, and to reduce as much as possible fringing due to a magnetic field diverging spatially from the foremost end of the magnetic head.
For noise reductions in a magnetic disk medium comprising a magnetic recording layer, the crystals of thin films are made minuscule with Br reductions, and exchange interactions among crystal grains are reduced.
It has been proposed to accomplish a medium with reductions in the transition width of magnetization and fringing upon recording by suppressing medium noise by control of crystal grains and anisotropic energy of the medium, control of orientation capability, exchange couple reductions, and use of a magnetization stabilizing structure. It has also been proposed to accomplish a thin-film magnetic disk wherein a guard band member made up of a non-magnetic material is located between adjacent recording tracks with a view to reducing side fringing of recording domains (JP-A 997419).
For the achievement of high linear recording density, perpendicular recording having an easy axis of magnetization in the perpendicular direction of a recording layer, and transverse recording having an easy axis of magnetization in a track direction within a film plane are available. These recording processes are expected to achieve an ever-higher recording density because demagnetization due to a demagnetizing field is more reduced than that in conventional longitudinal recording. Another proposal is made of a magnetic disk medium using a patterned medium comprising a substrate, a non-magnetic film such as an organic film or an Si film provided on the substrate, and unit minuscule recording areas obtained by embedding a magnetic thin film in recesses physically formed in the surface of the non-magnetic film. Never until now are a magnetic head used on the magnetic disk medium and how to record information thereon proposed.
A magnetic disk medium using such a patterned medium as mentioned above, for instance, a medium shown at 100 in FIGS. 3 and 4, comprises a disk form of substrate 102, a multiplicity of unit minuscule recording areas 104 formed of a magnetic material on the substrate 102 to magnetically record information thereon and located concentrically or spirally at an interval in a peripheral or radial direction, and a non-recording area 106 formed of a non-magnetic material that is embedded between unit minuscule recording areas. In the medium shown in FIG. 3, each of the unit minuscule recording areas 104 is in a rectangular form having a major axis and a minor axis, with the major axis direction aligned with the peripheral direction of the substrate, and in the medium shown in FIG. 4, each of the unit minuscule recording areas 104 is in a substantially cuboidal form. In the magnetic disk medium having such unit minuscule recording areas, the unit minuscule recording areas are individually isolated by the non-magnetic material from one another, so that fringing between adjacent unit minuscule recording areas can be eliminated. In the structure shown in FIG. 3, however, the improvement in the transfer rate of data is not always satisfactory. For the structure shown in FIG. 4, on the other hand, some contrivance is needed because perpendicular magnetic recording is carried out with a recording magnetic pole; that is, it is required to provide a return path or soft magnetic under layer in the medium, thereby achieving recording magnetic field enhancement.
It is therefore an object of the invention to provide a magnetic disk medium and magnetic recording system, which use a patterned medium structure as mentioned above so that the high transfer rate of data can be achieved with no fringing problem.